Fix typo in heading-increment rule name (#42)

* Fix typo in `heading-increment` rule name

* Also fix in test

Author: iansan5653

style/accessibility.json

@@ -4,7 +4,7 @@
     "no-duplicate-header": true,
     "no-emphasis-as-header": true,
     "no-generic-link-text": true,
-    "no-heading-increment": true,
+    "heading-increment": true,
     "no-space-in-links": false,
     "ol-prefix": "ordered",
     "single-h1": true,

test/usage.test.js

@@ -17,7 +17,7 @@ describe("usage", () => {
         "no-space-in-links": false,
         "single-h1": true,
         "no-emphasis-as-header": true,
-        "no-heading-increment": true,
+        "heading-increment": true,
         "no-generic-link-text": true,
         "ul-style": {
           style: "asterisk",